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Combining incidence and demographic modelling approaches to evaluate metapopulation parameters for an endangered riparian plant

View Article: PubMed Central - PubMed

ABSTRACT

Metapopulations are a central concept in ecology and conservation biology; however, estimating key parameters such as colonization rates presents a substantial obstacle to modelling metapopulations in many species. We develop spatial and non-spatial simulation models that combine incidence- and demographic-based approaches to build a relationship between observed patch occupancy, habitat turnover rates, colonization rates and dispersal scales. Applying these models to long-term observations of Pedicularis furbishiae (Furbish’s lousewort), a rare plant endemic to the Saint John River, we predict that observed habitat patches averaging 550 m in length receive colonizing seedlings with a yearly probability of 0.45 or 0.54, based on two different models. Predictions are consistent with a standard analytic metapopulation formulation modified to partition extinction drivers during the early and the late phases of a population’s life cycle. While the specific results rest on several simplifying assumptions, the models allow us to understand the impact that increasing rates of habitat turnover would have on the future survival of this species.

No MeSH data available.


Map of patches surveyed for potential Pedicularis furbishiae habitat along the Saint John River in Maine, USA. Points represent the 149 patches of suitable and unsuitable habitat used in our simulations.
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plw044-F1: Map of patches surveyed for potential Pedicularis furbishiae habitat along the Saint John River in Maine, USA. Points represent the 149 patches of suitable and unsuitable habitat used in our simulations.

Mentions: In 2008, the Maine Natural Areas Program mapped available habitat surrounding known populations of P. furbishiae (Fig. 1). To determine habitat suitability, expert opinion based upon slope and existing vegetation was used to classify river stretches as either ‘potential P. furbishiae habitat’, ‘too dry’, ‘too steep’ or ‘too flat’. Out of 72 km of river bank surveyed along a 100-km stretch of river, 35 km was identified as suitable habitat. The suitable habitat was composed of 61 discrete patches, of which 47 contained extant populations of P. furbishiae. There were two additional patches with suitable habitat for which it was not clear from the provided field notes whether or not P. furbishiae were surveyed for or detected in these patches, and so we excluded these patches when calculating the current occupancy rates. We defined habitat patches based on current contiguous areas of suitable habitat bounded by areas of unsuitable habitat. The mean length of the suitable habitat patches as measured along the river was 550 m (SD = 560 m, min = 29 m, max = 2436 m). These data also include 86 patches of unsuitable habitat, with a mean length of 410 m (SD = 390, min = 32, max = 1707).Figure 1.


Combining incidence and demographic modelling approaches to evaluate metapopulation parameters for an endangered riparian plant
Map of patches surveyed for potential Pedicularis furbishiae habitat along the Saint John River in Maine, USA. Points represent the 149 patches of suitable and unsuitable habitat used in our simulations.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940506&req=5

plw044-F1: Map of patches surveyed for potential Pedicularis furbishiae habitat along the Saint John River in Maine, USA. Points represent the 149 patches of suitable and unsuitable habitat used in our simulations.
Mentions: In 2008, the Maine Natural Areas Program mapped available habitat surrounding known populations of P. furbishiae (Fig. 1). To determine habitat suitability, expert opinion based upon slope and existing vegetation was used to classify river stretches as either ‘potential P. furbishiae habitat’, ‘too dry’, ‘too steep’ or ‘too flat’. Out of 72 km of river bank surveyed along a 100-km stretch of river, 35 km was identified as suitable habitat. The suitable habitat was composed of 61 discrete patches, of which 47 contained extant populations of P. furbishiae. There were two additional patches with suitable habitat for which it was not clear from the provided field notes whether or not P. furbishiae were surveyed for or detected in these patches, and so we excluded these patches when calculating the current occupancy rates. We defined habitat patches based on current contiguous areas of suitable habitat bounded by areas of unsuitable habitat. The mean length of the suitable habitat patches as measured along the river was 550 m (SD = 560 m, min = 29 m, max = 2436 m). These data also include 86 patches of unsuitable habitat, with a mean length of 410 m (SD = 390, min = 32, max = 1707).Figure 1.

View Article: PubMed Central - PubMed

ABSTRACT

Metapopulations are a central concept in ecology and conservation biology; however, estimating key parameters such as colonization rates presents a substantial obstacle to modelling metapopulations in many species. We develop spatial and non-spatial simulation models that combine incidence- and demographic-based approaches to build a relationship between observed patch occupancy, habitat turnover rates, colonization rates and dispersal scales. Applying these models to long-term observations of Pedicularis furbishiae (Furbish’s lousewort), a rare plant endemic to the Saint John River, we predict that observed habitat patches averaging 550 m in length receive colonizing seedlings with a yearly probability of 0.45 or 0.54, based on two different models. Predictions are consistent with a standard analytic metapopulation formulation modified to partition extinction drivers during the early and the late phases of a population’s life cycle. While the specific results rest on several simplifying assumptions, the models allow us to understand the impact that increasing rates of habitat turnover would have on the future survival of this species.

No MeSH data available.